Digestive organ stimulation using electrodes coupled to the organ have been proposed in a variety of applications. Currently these devices are typically delivered to the organ by way of a laparoscopic surgical procedure, i.e., in which an incision is made in the stomach and the leads are tunneled through the abdominal tissue.
Copending parent application Ser. No. 10/295,128, filed Nov. 14, 2002 and its parent application Ser. No. 09/847,884 now U.S. Pat. No. 6,535,764 both of which are incorporated in their entirety herein by reference, describe an endoscopically delivered stimulation device that is attached to the inside of the stomach from within the stomach.
Generally bipolar or monopolar leads have been provided in the proposed devices. Monopolar stimulation may cause inadvertent stimulation of tissue adjacent the stimulating lead. Organs immediately adjacent the stomach may have an unintended physiological response to such stimulation.
Accordingly when stimulating the stomach or other digestive organs it may be desirable to concentrate stimulation to a small area. However, digestive organ walls are relatively thin (typically about 10 mm) so that placement of bipolar electrodes on or through the walls in a manner that maintains electrical contact may also cause shunting between the electrodes. Additionally, the mucosa of the stomach has a high impedance further reducing the effectiveness of bipolar electrodes stimulating through the mucosa.